Time: 13:30-15:00 on Tue.,Nov.14, 2023
Venue：E109,Biomedicine Hall
Speaker：Dr. Alexey Amunts
Host：Dr.Yi Lin（吝易）
Title: What can we learn from structures of mitochondrial complexes
Abstract：
The mitoribosome translates specific mitochondrial mRNAsand regulates energy production that is a signature of all eukaryotic lifeforms. We present cryo-EM analyses of its assemblyintermediates, mRNA binding process, and nascent polypeptide delivery to themembrane. To study the assembly mechanism, we determined a series of the small mitoribosomal subunit intermediates in complex withauxiliary factors that explain how action of step-specific factors establishesthe catalytic mitoribosome. A delivery of mRNA is then performed bya helical repeat factor LRPPRC that forms a stable complex with a small bindingpartner SLIRP. In mammals, LRPPRC stabilises mRNAs co-transcriptionally, thus itlinks the entire gene expression system. Through the translation cycle, anascent polypeptide is delivered to the mitochondrial inner membrane, and wereport the mitoribosome structure bound to the insertaseOXA1, which elucidates the basis for protein synthesis coupling to membranedelivery. Together with experimental identification of functionally non-proteincofactors and specific rRNA and protein modifications, the datailluminate principal components responsible for the translation of geneticmaterial in mitochondria.
Biography：
AlexeyAmunts earned his PhD from Tel Aviv University for work on a plant PhotosystemI, and did a postdoc at the Laboratory of Molecular Biology in Cambridge oncryo-EM studies of a mitoribosome. In 2016, he established an independentgroup at Stockholm University focusing on mechanisms of mitochondrialtranslation and bioenergetics, and since 2020 he is an Associate Professor. Thegroup studies mitochondrial protein synthesis and energy production at themolecular and cellular level, and examines how these fundamental processes areaffected by natural selection and disease. He is currently a visiting Professorat Westlake University.